/*
 * C99-compatible strtod() implementation
 * Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <ctype.h>
#include <limits.h>
#include <stdlib.h>

#include "libavutil/avstring.h"
#include "libavutil/mathematics.h"

static char *check_nan_suffix( char *s )
{
    char *start = s;

    if ( *s++ != '(' )
        return start;

    while ( ( *s >= 'a' && *s <= 'z' ) || ( *s >= 'A' && *s <= 'Z' ) ||
            ( *s >= '0' && *s <= '9' ) ||  *s == '_' )
        s++;

    return *s == ')' ? s + 1 : start;
}

#undef strtod
double strtod( const char *, char ** );

double avpriv_strtod( const char *nptr, char **endptr )
{
    char *end;
    double res;

    /* Skip leading spaces */
    while ( isspace( *nptr ) )
        nptr++;

    if ( !av_strncasecmp( nptr, "infinity", 8 ) )
    {
        end = nptr + 8;
        res = INFINITY;
    }
    else if ( !av_strncasecmp( nptr, "inf", 3 ) )
    {
        end = nptr + 3;
        res = INFINITY;
    }
    else if ( !av_strncasecmp( nptr, "+infinity", 9 ) )
    {
        end = nptr + 9;
        res = INFINITY;
    }
    else if ( !av_strncasecmp( nptr, "+inf", 4 ) )
    {
        end = nptr + 4;
        res = INFINITY;
    }
    else if ( !av_strncasecmp( nptr, "-infinity", 9 ) )
    {
        end = nptr + 9;
        res = -INFINITY;
    }
    else if ( !av_strncasecmp( nptr, "-inf", 4 ) )
    {
        end = nptr + 4;
        res = -INFINITY;
    }
    else if ( !av_strncasecmp( nptr, "nan", 3 ) )
    {
        end = check_nan_suffix( nptr + 3 );
        res = NAN;
    }
    else if ( !av_strncasecmp( nptr, "+nan", 4 ) ||
              !av_strncasecmp( nptr, "-nan", 4 ) )
    {
        end = check_nan_suffix( nptr + 4 );
        res = NAN;
    }
    else if ( !av_strncasecmp( nptr, "0x", 2 ) ||
              !av_strncasecmp( nptr, "-0x", 3 ) ||
              !av_strncasecmp( nptr, "+0x", 3 ) )
    {
        /* FIXME this doesn't handle exponents, non-integers (float/double)
         * and numbers too large for long long */
        res = strtoll( nptr, &end, 16 );
    }
    else
    {
        res = strtod( nptr, &end );
    }

    if ( endptr )
        *endptr = end;

    return res;
}
